One out of every 33 people in the world is a migrant. Labor migration contributes to the rise in HIV rates globally, including in Central Asia. Yet, the associations between labor migration and HIV risk have been understudied using rigorous methods. This R21 application focuses on men from Central Asian (Kyrgyzstan, Tajikistan, Uzbekistan) countries who have come to work in St. Petersburg, Russia. It builds upon an NICHD- funded program of research in labor migration and HIV/AIDS prevention, as well as a partnership between the University of Illinois at Chicago and North-Western State Medical University named after I.I. Mechnikov. This study aims to build scientific knowledge on the multilevel risks associated with labor migration that can lead to HIV infection as well as the spectrum of involvement in HIV prevention and care among labor migrants. The mixed methods approach integrates biomedical, survey, and ethnographic methods. The project's aims are: Aim 1: To quantitatively investigate the associations between HIV infection and multilevel determinants related to labor migration at the levels of social policy, sociocultural practices, health and mental health, and sexual practices through a clinic-based case-control design. Aim 2: To qualitatively investigate the spectrum of involvement in HIV prevention and care among labor migrants (including experiences and perceptions regarding HIV testing, HIV infection, linkages to care, barriers to care, and the impact of labor migration) through minimally structured interviews of a purposive sample of HIV infected migrants, non-HIV infected migrants, providers, community advocates, and policymakers. The knowledge generated will inform the development of more targeted and effective strategies for HIV prevention, testing, and linkages to care for labor migrants.